Human pluripotent stem cell-derived cells endogenously expressing follicle-stimulating hormone receptors: modeling the function of an inactivating receptor mutation.

Follicle-stimulating hormone (FSH) is crucial in the development and regulation of reproductive functions. The actions of human FSH and its receptor (FSHR) and mutations therein have mainly been studied using in vivo models, primary cells, cancer cells and cell lines ectopically expressing the FSHR. To allow studies of endogenous FSHR function in vitro, we differentiated FSHR-expressing cells from human pluripotent stem cells. FSH stimulation of the wild-type (WT), but not the inactivating Finnish founder mutant (A189V) receptor, activated the canonical cyclic adenosine monophosphate (cAMP)-dependent signaling pathway and downstream mediators. To investigate protein-protein interaction partners of FSHR at resting state and upon FSH stimulation, we expressed FSHR in HEK293 cells followed by affinity purification mass spectrometry analyses. We found 19 specific high-confidence interacting proteins for WT FSHR and 14 for A189V FSHR, several of which have been linked to infertility. Interestingly, while only WT FSHR interacted with FSH, insulin-like growth factor 1 receptor (IGF1R), for example, interacted with both WT and A189V FSHR upon FSH stimulation. In conclusion, our protocol allows detailed studies of FSH action and disease modeling in human cells endogenously expressing FSHR.

Maternal diet and fatty acid pattern of breast milk.

The effect of habitual maternal diet on the fatty acid composition of breast milk was evaluated by conducting a dietary survey of lactating mothers and by analyzing their breast milk samples. The mean energy intake of the mothers was 9.8 MJ during the first survey week (20 mothers, 6-8 weeks post partum) and 8.6 MJ during the second survey week (13 mothers, 17-22 weeks post partum). Protein, fat and carbohydrate intake comprised 16%, 39% and 45% of the total energy intake, respectively. The breast milk samples contained 3.8% fat. Half of the fatty acids of the diets and breast milk were saturated (S), and one third were monoenoic. Polyunsaturated (P) fatty acids comprised 15% in the diets and 13% in the breast milk. The average P/S ratio was 0.3 both in the diets and breast milk samples. Carbohydrate intake correlated negatively (p less than 0.05) with arachidic acid of breast milk, and both protein and fat intakes correlated positively (p less than 0.05) with palmitic acid of breast milk. The maternal diet had no effect on the total fat content of breast milk. A positive correlation was found between the saturated (p less than 0.05) and polyunsaturated (p less than 0.01) fatty acids of maternal diet and breast milk. As to the single fatty acids, the only significant correlation was found with linoleic acid (p less than 0.01). However, the variation of linoleic acid intake explained only about 27% of the variation occurring in the breast milk.

Seasonal and nutritional effects on serum proteins and urea concentration in the reindeer (Rangifer tarandus tarandus L.).

1. The effects of seasonal conditions and nutrition on serum proteins and serum urea concentrations were studied in female reindeer and reindeer calves in Finland. With the exception of one group in winter, the reindeer were roaming wild in the forests. This one group was kept in captivity, out of doors, on a comparatively high nutritional plane. One group lived wild during the winter in very poor nutritional conditions. 2. A very clear seasonal variation in the serum protein and urea concentration was found. The serum protein concentration was low in late winter and increased rapidly during the summer, being high in the autumn. The serum urea concentration was also low in the winter and high in the summer. In the autumn, however, the serum urea concentration was again low. 3. Changes in the serum protein concentration were normally associated with the serum globulins. Only in the very poor-nutrition group did the albumin content decrease significantly. As a result of the large changes in the concentration of serum globulins, there were also considerable changes in the albumin: globulin ratio. 4. The serum protein concentration was much lower in the reindeer calves than in the adult reindeer. The concentration of globulins in particular was much lower than in the adults.